Kinetic study of the anionic polymerization of propylene sulfide. VI. Influence of the solvent and of several cryptating agents

Abstract

Abstract Solvent effect upon the reactivity of ion pairs has been examined for the cesium salt of polypropylene sulfide. k ± increases with the dielectric constant of solutions. The size effect of the counterion upon the propagation rate constants has been studied in tetrahydrofuran (THF) at −30°C. Values of the dissociation constant K D and of the interionic distance parameter a have been deduced from conductivity measurements made on seeds of living polypropylene sulfide with the cryptate Na + ∥222∥ as counterion. k ± and k − were determined for several cryptated counterions. Cryptated ion pairs are more reactive than free ions.